Apparatus for finishing wood and the like



Feb. 2, 1965 A. M. JACOBI 3,

APPARATUS FOR FINISHING WOQD AND THE LIKE Filed Feb. 7, 1962 3Sheets-Sheet 1 ARNO M. JACOB/ EIl'E-r- 3 BY ATTORNEYS Feb. 2, 1965 A. M.JACOB! APPARATUS FOR FINISHING WOOD AND THE LIKE Filed Feb- 7, 1962 3Sheets-She et 2 INVENTOR. ARNO M. JACOB] ATTORNE Y5 Feb. 2, 1965 A. M.JACOB] 3,167,889

APPARATUS FOR FINISHING WOOD AND THE LIKE Filed Feb. 7, 1962 3Sheets-Sheet 3 6 l Q 12 66 2;"! e9 68 "13 INVENTOR ARuo M. JncoanATTORNEYS United States Patent 3,167,889 APPARATUS FOR FINISIEQG WGODAND THE LIKE Arno M. Jacobi, Belmont, Calif, assignor to Walter Jacobi &Sons, Inc., Belmont, Calif., a corporation of California Filed Feb. 7,19,62, Ser. No. 171,604 19 Claims. (Cl. 51--141) The present inventionrelates to improvements in a finishing apparatus and particularly to anapparatus for providing finished surfaces on irregularly shaped surfacesof wood and the like.

Conventionally wood and similar materials are finished by sanding orlike processes to provide a smooth surface, and many different machineshave been developed for carrying out this process. While these machinesare eminently suitable for use on most fiat and simple curved surfaces,they are generally not suitable for practical operation on work which isirregularly curved and wide.

Accordingly, it is a primary object of this invention to provide anapparatus for finishing irregularly shaped or curved surfaces that giveshighly satisfactory results and has a practical and elficient mode ofoperation.

Another object of the invention is to provide an apparatus for finishingirregular surfaces which utilizes a belt having an abrasive surfacewhich is resiliently pressed against 'all areas of the irregularsurface.

A further object of this invention is to provide an apparatus of thecharacter described which maintains a pressure against the recessedportions of the surface being finished equal to or greater than thepressure exerted against the raised portions of the surface.

Still another object of the invention is the provision of a finishingapparatus of the character described that is capable of sustained highspeed operation.

A still further object of the invention is to provide an apparatus forfinishing a curved surface with a rotating abrasive belt that also hasoscillatory motion at the work to provide an especially good finish.

Further objects and advantages of my invention will be apparent as thespecification progresses, and the new and useful features of myfinishing apparatus will be fully defined in the claims attached hereto.

In its broad aspect, the present invention embraces a belt finishingapparatus having any of a variety of abrasives on a surface thereof. Theabrasive may be sand, carbonlndum, corundum, emery abrasive, jewelersrouge, or others. However, the preferred abrasive is sand and theapparatus will usually be a type of belt sander. Accordingly, thedescription will be mainly directed to a belt sander constructedaccording to the invention.

The preferred forms of my invention are illustrated in the accompanyingdrawings, forming a part of this specification, in which: 7

FIGURE 1 is an elevational view of a belt sander constructed accordingto the invention;

FIGURE 2, a cross-sectional view taken in the plane of line 2-2 ofFIGURE 1;

, FIGURE 3, a bottom view of the apparatus of FIG- URE 1 as seen fromthe position where sanding is effected, and with the belt removed toillustrate the parts supporting and shaping the belt;

FIGURE 4, a cross-sectional view taken in the plane of line 44 of FIGURE2;

FIGURE 5, an enlarged view of the fragmentary portion of FIGURE 2 partlybroken away to better illustrate certain of the parts;

FIGURE 6, a perspective view of a backing unit suitable for use in analternate embodiment of the invention; and

FIGURE 7 is a partial plan view of FIGURE 1 showing one means forimparting oscillating motion to the belt.

While I have shown only the preferred form of my invention, it should beunderstood that various changes or modifications may be made within thescope of the claims attached hereto without departing from the spirit ofthe invention.

Referring to the drawing in greater detail, there is shown in FIGURE 1an apparatus for finishing irregularly shaped surfaces on a work pieceto be finished, comprising a belt 11 having an abrasive surface 12containing sand or the like and drive means 13 for moving said beltcircumferentially and through work station 14. The apparatus alsocomprises a backing unit 16 at work station 14 adjacent to belt 11 onthe side opposite abrasive surface 12. This backing unit presents anirregular surface which matches the configuration of the desiredfinished surface.

Drive means 13 may be constructed in a variety of ways and herecomprises rollers 17 for guiding belt 11, motor 18 for supplying power,and drive belt 19 for transferring power from motor 18 to belt 11. Motor18 is also herein used to drive conveyor means 21 for conveying workhaving an irregularly shaped surface to be finished through work station14. In this way, the surface of the work to be finished is moved injuxtaposed position with respect to the abrasive surface 12. In thissystem, power is transferred from motor 18 to conveyor 21 through drivebelts 22 and pulleys 23 which are geared to each other as shown.

In the form illustrated in FIGURE 1, conveyor means 21 comprises rollers24, belt 26 and roller 27 for adjusting belt tension. A work piece 28 iscarried through work station 14 on conveyor 21 with the direction of thework being similar to the direction of the moving belt but at a slowerspeed. This method of moving the work is particularly satisfactory andaccordingly is preferred. However, it is also possible to use othermeans for moving the work through the station with the important struc:ture being that which holds the work at the desired distance withrelation to the abrasive surface.

The sanding belt 11 normally assumes a flat configuration with rollers17 being substantially cylindrical. However, the belt is fiexible andassumes the desired irregular configuration at work station 14. In orderto move the belt at the desired high speed and still have its surface inthe proper configuration at the work station, means is provided forshaping the belt in front of the work station to form a predeterminedirregularly shaped surface of substantially the same shape as theirregularlry shaped surface of the backing unit. As shown in FIGURES 1and 2, this means may comprise a roller 29 mounted for rotation in mainframe 31, which roller has an irregular surface designed to preshapebelt 11.

After passing through work station 14, the belt is preferably reshapedto a flat configuration. This may be accomplished by roller 32 which isalso journaled for rotation in main frame 31, and which has asubstantially circular, cylindrical surface. The shaping of the belt isprovided by maintaining the necessary tension in the belt, and thistension is provided by adjustable roller 33.

In the embodiment shown in FIGURES 1 through 5, the backing unit 16comprises a frame 34, a plurality of U-shaped members 36 carried onframe 34 having outer surfaces 37 relatively movable to provide anirregularly curved surface across the width of the belt 11, and meansfor resiliently holding members 36 in position. As best seen in FIGURE4, frame 34 is in the form of an I beam having bolts 38 carried in pairson each side. Each pair of bolts is pivotally attached to U-shapedmembers 36 through brackets 39 and cotter pins 41. Brackets 39 areattached to members 36 by welding, brazing or any other suitable means.a

The distances of faces 37. of members 36 from'the frame 34 arerestricted by nuts 42, and adjusted by rotation thereof. The faces 37are resiliently held at these allowed distances by compression-springs43. As best seen in FIGURES 4 and 5, compression springs 43 .are carriedon bolts 38, and bear against washers 44 which in turn arev adjustablypositioned by'nuts 46. Thus, nuts 46 adjust the compressive force: ofsprings 43. Preferably, the compression is adjusted to be greateston thesprings for the members as atthe recessed portions of the curvedsurfaces being sanded, see FIGURE 2.

In order to cushion the belt 11 and allow easy passage of the shapedsurfaces 37 of members 36 thereunder, a

flexible cushion 47 is provided on members 36, and the.

Shock absorber 52 preferably contains a plastic pad 53.

at the side first contacting the work, and a felt pad '54 at the sidelast in contact with the work, .see FIGURE 4. The steel strip is rivetedto members 36 at a plurality of 3,1s7,sea

places. F or example, rivets 56 hold the plate at a central position'andrivets 57 hold it at each side. Note that rivets 57 are held in slots 58on plate or strip 48 to allow expansion of the plate as it heats upduring operation of the apparatus. The plastic pad 53 and felt pad 54glued or otherwise bonded to the steel plate, and cloth facing 49 isglued or bonded to the plastic pad 53 and felt pad 54.

Preferably the plastic used for fabricating plasticpad 53. is alaminated phenol-formaldehyde resin such as that sold under the tradename Formica. other plastics or equivalent materials are suitable,-Similarly, different materials maybe used for the feltpad154= and thecloth facing 49; The important consideration is the provision of amaterialthat will act as a cushion and also allow the belt tomoverapidly thereby without un'dt'ie wear-undersea.

As indicated above, the adjustable springs used to resil-,

iently push the U-shapedmernbers toward the work are preferred. However,other systems are within the scope of the invention. For example, airpressure could be used.

instead of-spring means. An embodiment using. air pressure isillustrated in FIGURE 6 wherein a flexible hose such as a fire hosecarrying air under. pressure is used.

Thus in FIGURE 6, there is shown a backing unit 16, comprising frame 34in the shape of a channel shaped member having U-shaped members 36heldthereto. by

flexible straps 59. Straps 59 are pivotably attached as through rivets61, and the straps are designed of a length sllflicient to allow theouter. surfaces of the members 36 to assume the desired configuration.Cloth facing 49 is carried on the members 36 through a cushionconstructed.

according to cushion 47 in a manner similar to that described in detailforthe. embodiment of FIGURESYI through When air pressure is exertedwithin fire hose 62, memhere 36 are resiliently forced into position. Inthis way. substantially equal pressure is exerted on all ofthe.

U-shaped members and therefore the pressure is maintained uniform acrossthe irregularly shaped belt 11:.

The apparatus is particularly suitable for finishing.

one pass, and each operation may be accomplished at However, many Forexample, a suitable curvedpiece' i comparatively high speeds. 1 Thus itis seen that the apparatus of this invention is. particularly valuablewhen the irregular surface to be finished is a curved cylindric surface,that is, a surface which. is formed by a straight line moving in acurved path including corrugated surfaces and combinations of curvedandstraight surfaces. V Thebelt 11 is oscillated in a direction parallelto the axis of the closedloop by .a means disclosed in'FIGURE 7, whereinthe rollers 17' are 'rotatably mounted within frame members 65. Thevmotor 18 has a pulley 66' on theshaft thereof which drives a belt 67Thebelt engages anddrives a pulley rotatably mounted on a shaft 69. The

shaft 69 alsohas rotatably mountedithereon a cylinder 70 whichcylinder'is fixedtoand rotated by the'pulley 68. The cylinder has areturnscrew thread 71 .cut into the body thereof.- A follower 72 mountedon. one of the frame members has an end thereof in the return screwthread 71 and moves in a reciprocatory or oscillating mannerwhen thecylinderis rotated, thus giving an oscillating motionto the frame andthe roller 17. This causes the working face of the beltll to be moved inan oscillating manner past the work station 16 so that the belt is movedtransversely of the work so that unsightly grooves will not be cut inthe work." A spring '73 may be provided betweenthe frame carrying therolier 17 and a stationary part of the machine to maintain the followerin the return screw thread. I

However, it is also seen .that'machine could be used 1 ample, work couldbe rotated through the work station or otherwise passed therethroughoperations, if. desired.

1. An apparatus for finishing irregularly shapedsurfaces on wood and thelike, comprising a belt having an abrasive surface, means for movingsaid belt through a work station, means for moving work through. saidwork station with the surface of the work-to be finished in juxtaposedposition withrespect tothe abrasive surface of the belt, a backing unitat saidwork station adjacent to said moving belt on the side oppositethe abrasive surface, said backing unit having an irregularsurfaceof aconfiguration which matches the configuration of a desired finishedsurface, and means for shaping the belt in front 'of the work station toform, a predetermined irto give a variety of 1 other regularly shapedsurface of substantially the same shape as the irregularly shapedsurface of the backing unit.

2. An apparatus for finishing irregularly shaped surfaces onwood and'thelike, comprisingabelt.having an abrasive 'surface,means for moving saidbelt'througha work station, means for movingwork through said workstation with the surface of the work tobe vfinishedin juxtaposedposition with .respectto the abrasive surface of. the belt, a backing.unit at said. Work station adjacent to said moving belt on the sideopposite the abrasive surface, said backing unit havingan irregularsurface of a configurationwhich matches the configuration of a desiredfinished surface, means for'shapingthe belt in front of the work stationto form a predetermined irregularly shaped surface of substantially thesame shape as the irregularly shaped surface of the backing unit, andmeans for reshaping the belt to a substantally flat'configuration afterthe belt has left the work station.v

'3. The apparatus defined in claim 2, in which the belt ismoved througha closed loop and is. provided with an oscillating motion atthe workstation, said oscillating {notion being in a line parallelto the axis ofthe closed oop.

4. The apparatus defined in claim 2, in which the work is moved linearlythrough the work station substantially tangentially totheflloop at aspeed slower than the belt movement'around the loop,

5. An apparatus for finishing irregularly shaped surfaces on wood andthe like, comprising acontinuous belt having a surface containing anabrasive material, means for moving said belt circumferentially in alooped path which passes through a work station, and a backing unit atsaid Work station adjacent to said belt on the side opposite saidabrasive surface, said backing unit containing a frame, a plurality ofmembers carried on said frame having surfaces relatively movable toprovide an irregularly curved surface across said belt, a singleflexible metal plate carried on said members and extending across theentire width of said belt, slotted holding means for holding said plateon said plurality of members allowing faces on Wood and the like,comprising a continuous belt having a surface containing an abrasivematerial, means for moving said belt circumferentially in a looped pathwhich passes through a work station, means for conveying work throughsaid Work stationin position tobe sanded by said abrasive surface ofthebelt, and a backing unit at said work station adjacent'to said belt onthe side opposite said abrasive surface, said backing unit containing aframe, a plurality of members carried on said frame having surfacesrelatively movable to provide an irregularly curved surface across saidbelt, means for resiliently holding said members in position to presenta desired irregular configuration adjacent the belt, a flexible cushionon the irregularly curved surface provided by the members, and alubricant on said flexible cushion.

7. The apparatus defined in claim 6, in which compres sion spring meansare used for resiliently holding the members in position.

8. The apparatus defined in claim 6, in which pneumatic pressure is usedfor resiliently holding the members in position whereby a substantiallyuniform pressure is provided over the entire surface of the flexibleplate.

9. The apparatus defined in claim 6, in which the flexible cushioncomprises a flexible metal strip, a shock absorber in the form of aplastic sheet mounted on the flexible metal strip, and a cloth facing onsaid shock absorber having the lubricant on said cloth facing.

10. An apparatus for finishing irregularly shaped surfaces on Wood andthe like, comprising a continuous belt having a surface containing anabrasive material, means for moving said belt circumferentially in alooped path which passes through a work station, means for conveyingwork through said work station in position to be sanded by said abrasivesurface of the belt, a backing unit at said work station adjacent tosaid belt on the side opposite said abrasive surface, said backing unitcontaining a frame, a plurality of members carried on said frame havingsurfaces relatively movable to provide an irregularly curved surfaceacross said belt, means for resiliently pression spring means are usedfor resiliently holding the members in position.

12. The apparatus defined in claim 10, in which pneumatic pressure isused for resiliently holding the members in position whereby asubstantially uniform pressure is provided over the entire surface ofthe flexible plate.

13. The apparatus defined in claim 10, in which the flexible cushioncomprises a flexible metal strip, a shock absorber in the form of aplastic sheet mounted onthe flexible metal strip, and a cloth facing onsaid shock absorber having the lubricant on. said cloth facing.

14. The apparatus defined in claim 10, in which the belt for moving saidbelt circumferentially in alooped path holding said members in positionto present a desired irregular configuration adjacent the belt, aflexible cushion including a flexible'metal plate mounted on theirregularly curved surface provided by the members, a lubricant on saidflexible cushion, means for shaping the belt in front of the workstation to form a predetermined irregularly shaped surface ofsubstantially the same shape as the irregularly shaped surface of thebacking unit, and

means for reshaping the belt'to a substantially flat configuration afterthe belt has left the work station.

11. The apparatus defined in claim 10, in which comwhich passesthroughawork station, means for conveying Work through said workstation inposition to be sanded by said abrasive surface of the belt, a backingunit at said work station adjacent to said belt on the side oppositesaid abrasive surface, said backing unitcontaining a frame, a pluralityof U-shaped members each having a flat surface and bolts adjustably helda fixed distance from said frame to present the flat surfaces along aline which generally defines an irregular curved surface across saidbelt, compression springs carried onthe bolts of said U-shaped membersfor urging the surfaces of said members resiliently away from saidframe, a flexible cushion on the irregularly curved surface defined bysaid mem-' bers, and a graphite lubricant on said flexible cushion.

16. The apparatus defined in claim 15, in which the flexible cushioncomprises a flexible metal strip, a cloth facing having the lubricant ona surface thereof, and a shock absorber between the flexible metal stripand the cloth facing which includes a plastic pad at the side firstcontacting the work and a felt pad at the side last in contact with thework. 7

17. The apparatus defined in claim 16, in which the metal strip is steeland the plastic is a phenolformaldehyde plastic.

18. The apparatus defined in claim 16, in which the belt is alsooscillated at the work station in a direction perpendicular to thegeneral movement of the belt.

19. The apparatus defined in claim 16, in which the work is movedlinearly through the work station substantially tangentially to the loopat a speed slower than the belt movement around the loop.

References Cited in the file of this patent UNITED STATES PATENTS761,023 Yarnell May 24, 1904 804,902 Tyden Nov. 21, 1905 807,809 ClemansDec. 19, 1905 900,249 Wysong Oct. 6, 1908 1,096,882 Wysong May 19,1914-- 1,493,779 Humphreys May 13, 1924 1,927,330 Williams Sept. 19,1933 2,279,782 Fowler Apr. 14, 1942 2,594,646 Hendrickson Apr. 29, 19522,618,913 Plancon et al Nov. 25, 1952 2,624,160 Harper Ian. 6, 19532,633,679 Cross et a1. Apr. 7, 1953 2,693,669 Riedesel Nov. 9, 19543,022,611 Schaller ,Feb. 27, 1962

1. AN APPARATUS FOR FINISHING IRREGULARLY SHAPED SURFACES ON WOOD AND THE LIKE, COMPRISING A BELT HAVNG AN ABRASIVE SURFACE, MEANS FOR MOVING SAID BELT THROUGH A WORK STATION, MEANS FOR MOVING WORK THROUGH SAID WORK STATION WITH THE SURFACE OF THE WORK TO BE FINISHED IN JUXTAPOSED POSITION WITH RESPECT TO THE ABRASIVE SURFACE OF THE BELT, A BACKING UNIT AT SAID WORK STATION ADJACENT TO SAID MOVING BELT ON THE SIDE OPPOSITE THE ABRASIVE SURFACE, SAID BACKING UNIT HAVING AN IRREGULAR SURFACE OF A CONFIGURATION WHICH MATCHES THE CONFIURATION OF A DESIRED FINISHED SURFACE, AND MEANS FOR SHAPING THE BELT IN FRONT OF THE WORK STATION TO FORM A PREDETERMINED IRREGULARLY SHAPED SURFACE OF SUBSTANTIALLY THE SAME SHAPE AS THE IRREGULARLY SHAPED SURFACE OF THE BACKING UNIT. 